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ESTRADIOL LEVEL
An estradiol test usually measures the amount of estradiol
in the blood. This test is used to evaluate ovarian,
placental or adrenal function particularly when certain
types of ovarian tumor are suspected or when there is late
or abnormal development of male or female body
characteristics. In assisted reproductive technology (ART),
serial measurements of serum estradiol and ultrasound
imaging of ovarian follicles are used to observe the ovarian
response to stimulation.
Astradiol is a steroid hormone that has many important
functions in females. Estradiol is mostly synthesized in and
secreted from the placenta, ovarian follicle, and adrenal
cortex. It is responsible for growth of the uterus,
fallopian tubes and vagina; promotion of breast development;
maturation of the external genitalia; deposition of body fat
in a female distribution; and termination of linear
development. Estradiol stimulates the creation of the
endometrium in the first half of the menstrual cycle.
During the early part of the menstrual cycle, estradiol
levels remain constant. This is followed by a rapid increase
reaching a peak the day before or the day of the Leutinizing
Hormone surge. It is generally believed that the rise in
estradiol is the factor, which causes LH release. Following
ovulation there is a drop in estradiol followed by a second
rise, which corresponds with the development of the corpus
luteum.
At menopause, estrogen concentrations in the body fall to
very low levels. This decrease is often accompanied by
vascular instability, a rise in incidence of heart disease,
and an increasing rate of bone loss. Astrogen replacement
for lessening of menopausal symptoms or to prophylax against
heart disease and osteoporosis has become very common.
Estradiol levels are used to assess fertility, amenorrhea
and puberty in girls. Measurement of estrogen levels is also
useful to monitor and titrate replacement therapy
particularly when the endpoints are long-term health rather
than the immediate relief of symptoms.
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